The invention relates to a contactless plug connector for electromagnetically connecting a corresponding mating connector. In particular, the invention provides a contactless plug connector and contactless plug connector system including a transmitting circuit and/or receiving circuit for transmitting and/or receiving a radio wave of a predetermined carrier frequency.
Generally, the invention relates to contactless plug connectors for data transmissions. A contactless plug connector of the invention may, for instance, comply with known connection interface standards, for instance, Ethernet, USB, CAN, IO-link and RS485. In more detail, the contactless plug connector of the invention may be utilized for industrial devices such as robots, material handling systems, injection molding devices, mining & harvesting equipment and transportation vehicles amongst others and for portable data processing devices such as mobile phones, mobile storage units, mobile music players, mobile video presentation devices, namely for allowing data and power connections under hostile environmental influences.
Industrial devices often rely on cables and connectors, operating in a hostile environment, which wear and tear and do not allow for rotation limiting the freedom of movements of these devices.
Portable data processing devices have evolved in the past from quasi stationary laptop computers to mobile devices allowing for an indoor and outdoor usage. Due to the portability, mobile devices are carried around and are thereby exposed to hostile environmental influences, e.g. dust, dirt, humidity, rain, acid liquids, heat, cold, shock and mechanical stress. In this respect, the connectors of a mobile device, positioned at the boundary between an outside and an inside of the mobile device, require adaptation to the newly diversified operating environments.
In the past, plug connectors were realized as electrical connectors wherein an electrical contact was established between the plug connector and a corresponding mating connector, i.e. receptacle connector.
However, electrical connections are limited to a direct connection between two electrical contacts and the tolerance regarding misalignment between contacts is not very high. Dust, dirt, shock and mechanical stress may adversely effect the establishment of an electrical connection between plug connector and receptacle connector.
Electrical connections are also sensitive to humidity e.g. rain as water may short-circuit electrical contacts in an unintended manner. Further, environmental influences may also deteriorate the contact surface reducing the conductivity of the connector in a mated state.
Accordingly, electrical connectors, though reasonable for an indoor operating environment, are disadvantageous for portable devices operable under more hostile environmental influences.
In the recent past, wireless interfaces have become popular for mobile devices as they overcome disadvantages inherent to an electrical connection. Radio waves do not require a direct contact (i.e. electrical connection).
Accordingly, mobile devices have been designed to incorporate the appropriate radio wave transceiver modules in the housing of the mobile device. In particular, by sealing transceiver modules and other electrical circuits within the housing of a mobile device, it is possible to also established data connections with a mobile device under hostile environmental influences.
However, wireless connections are adversely affected by electromagnetic interference. The electromagnetic influence may have multiple causes and may depend on the radio band in which wireless communication is performed. Industrial, scientific and medical (ISM) radio bands have been initially reserved for emission of radio frequency energy from appliances having other purposes than communication (e.g. microwave oven).
Since electromagnetic interference is expected in the ISM radio bands, governments have permitted unlicensed operation to appliance limiting the electromagnetic emission to the ISM radio bands only and fulfilling certain power requirements.
This financial incentive is a crucial aspect to the operation of many devices and may also be considered a reason for the existence of various wirelessly connected devices communicating in the ISM radio bands. Presently, the number of devices operating in the same ISM radio bands increases and in total a considerable amount of electromagnetic interference is emitted.
Under such constraints, wireless connections are not as robust as electrical connections. In particular, for wireless interfaces a user lacks a clear response whether or not a wireless connection can be established. The amount of interference may decide between successful or non-successful wireless connection establishments. However, as the amount of interference is difficult to estimate and may also change over time, wireless interfaces are considered not as robust as electrical connector interfaces. In other words, for indoor environments electrical plug connectors may be regarded fail-safe in view of a successful connection establishment whereas this is not the case for wireless interface.
Accordingly, technical prejudices against the robustness of wireless connections had to be overcome to arrive at the invention of providing a contactless plug connector with a radio wave antenna.